The specific aims of this program are to evaluate present techniques for flow cytometry of urologic specimens, which are already comparable to conventional cytology, and to encourage further improvements in the technology by research and development through a collaborating network of the major laboratories working in this field. It is expected that this will facilitate transfer of flow cytometry technology from the research to the clinical laboratory, thereby increasing clinical access nationwide to cytologic diagnosis, providing standardized diagnostic criteria and objective rather than (the current) subjective evaluations of cytologic samples. By encouraging the collaboration of cell biologists and engineers with pathologists (cytologists) and urologists, it is expected that new diagnostic features will be devised based on cell biology rather than empirical morphologic criteria, and that this will permit still earlier recognition of cancer (precancer cells), more precise classification and more complete prognostic information for the clinical management of patients with proven or suspected bladder tumors. Less trained laboratory personnel will be able to supplement or replace the highly skilled and highly paid cytotechnologists who perform screening examinations for detection of early carcinoma and precancerous lesions (carcinoma in situ). As a result, it will be possible to screen high risk populations at lower cost, and to lessen the cost of monitoring conservative treatment of bladder tumors by using automated flow cytometry examinations with less frequent hospitalizations for cystoscopy.